Partial hydrogenation of 1, 4-butynediol



UnitedStates Patent PARTIAL HYDROGENATION OF 1,4-BUTYNEDIOL Eugene V. Hort, Westfield, N.J., assignor to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Dec. 23, 1957, Ser. No. 704,240

8 Claims. (Cl. 260-635) This invention relates to the catalytic partial hydrogenation of 1,4-butynediol to 1,4-butenediol.

The partial hydrogenation of 1,4-butynediol to 1,4- butenediol, hereinafter referred to as, respectively, butynediol and butenediol, in the presence of a number of diiferent catalysts and by a number of different procedures is known. However, such previously proposed processes have been deficient for a number of reasons, including the necessity for using specially prepared or poisoned catalysts, high pressures, careful control to avoid further reduction of the butenediol to butanediol and production of undesirable by-products and the like. Whereas both palladium andRaney nickel have been employed for such partial hydrogenation, they had to be stopped to prevent such further reduction of the butenediol to butanediol.

It is an object of this invention to provide a hydrogenation process for the reduction of butynediol to butenediol which is not subject to the above disadvantages. Another object of this invention is the provision of an automatic or self-stopping process for the hydrogenation of butynediol to butenediol. Other objects and advantages will appear as the description proceeds.

The attainment of the above objects is made possible by the instant inventive process for the catalytic hydrogenation of butynediol to butenediol comprising treating butynediol with hydrogen at a temperature of about 60 to 120 C. and a pressure of about 0 to 6 atmospheres gauge in the presence of a nickel catalyst. It has been found that by use of temperatures in the above range, and the relatively low pressures of 0 to 6 atmospheres gauge, the absorption of hydrogen automatically and spontaneously stops when the butenediol stage has been reached. When temperatures lower than those specified above are employed in the same system, butanediol is produced, while at higher temperatures than those specified, an ever increasing amount of butanol is formed. The catalyst is not inactivated by the process of this invention and may be reused repeatedly.

In carrying out the process of this invention, the butynediol is maintained in liquid condition, at a pH of no more than about 7, preferably in solution in an inert solvent such as ethyl alcohol or other alcohols, dioxane, or the like, but preferably in an aqueous solution. Concentrated solutions are preferred, an aqueous solution having a concentration of at least about 20%, and preferably 35 to 40%, having been found highly advantageous and convenient. If desired, undiluted liquid butynediol may be used. Such solutions are available commercially at a pH of about 2.5 to 6.

The nickel catalyst employed in the process of this invention is preferably maintained in the liquid butynediol reaction medium in finely divided form. A Raney-type nickel catalyst (such catalysts are described in U.S. Patent No. 1,628,190) is preferred as yielding optimum results. This type of catalyst is readily prepared by treating an aluminum-nickel alloy with caustic soda to dissolve out the aluminum and leave the nickel in a highly divided and "ice particularly effective form. The amount of nickel catalyst employed will generally range from about 0.1 to

10%, and preferably'from about 0.5 to 3% by weight of the butynediol, but such amount is not critical since the catalyst is not deactivated during the hydrogenation and may be reused. For a given amount of butynediol to be hydrogenated, the rate of hydrogenation will vary directly with the amount of catalyst employed.

In some instances, further improved results are obtained when the butynediol-nickel catalyst system also contains dispersed upon the catalyst about 3 to 15% of copper by weight of the nickel catalyst. When an aqueous solution of butynediol is employed, a watersoluble copper compound is preferably added thereto,

particularly the copper salts of strong acids such as cop,- per sulfate, copper chloride, and copper nitrate, and the copper salts of weak acids such as copper cyanide, copper formate, copper acetate and copper carbonate. Copper oxide may also be used. Some of these compounds are also soluble in organic solvents. The particular copper compound employed will of course be dependent upon the liquid reaction medium. The nickel replaces the copper from the solution and any residual soluble copper is reduced during the hydrogenation. The precipitated copper is dispersed on the nickel catalyst. The hydrogenation of the butynediol in the reaction medium is carried out by maintaining. an atmosphere of hydrogen over the surface of the reaction medium, con; tact therewith being facilitated by agitation, as by rocking; or shaking the reaction vessel, or by stirring the reaction medium with a high-speed propeller or the like. Since, as pointed out above, the reaction is" auto matic or self-stoppIng, completion'of the. desired partial hydrogenation of the butynediol to the butenediol' stage is readily apparent when absorption of hydrogen. ceases.

- The reaction mediumis maintained within the above .de-

fined temperature range during the hydrogenation, and pressure is applied by maintaining the atmosphere over the reaction medium connected to a source of hydrogen at the desired pressure. In operation, the maximum allowable pressure should be increased by no more than 2 atmospheres (gauge) for each 20 rise in temperature above 60 C. Thus, at 60 to C. not more than 2 atmospheres hydrogen pressure should be employed, at 80 to C., not more than 4 atmospheres, and at 100 to 120 0., not more than 6 atmospheres.

The following examples, in which parts are by weight unless otherwise indicated, are illustrative of the instant invention and are not to be regarded as limitative.

Example 1 A rocking autoclave containing 230 g. (1 mole) of 36.2% aqueous butynediol and 4.0 g. of aqueous Raney nickel paste (50% nickel) is held at 90 C. while maintainlng a hydrogen pressure of about 2 atmospheres gauge therein. After nine hours, the absorption of hydrogen stops spontaneously.

The product is filtered from the catalyst and distilled at reduced pressure. After removal of the solvent and a forerun of 45% of crude diols, 45% of butenediol, based on the starting butynediol, is obtained, B.P. C./mm., S.P. 7 C. (solidification point), N 1.4765 (index of refraction).

Example 2 The procedure of Example 1 is repeated, except that 226 g. (1 mole) of 38.1 aqueous butynediol is hydrogenated at C. and about 5 atmospheres gauge pressure. After four hours, the absorption of hydrogen stops spontaneously. After working up, 40% of crude diols and 40% of butenediol is obtained.

Example 3 The procedure of Example 1 is repeated except that 1.0 g. of copper acetate is added to the solution and 6,0 g. (solids) of Raney nickel is used. After twelve hours the reaction stops spontaneously. After working up as described, there is only a small forerun of crude diols, followed by 35% of butenedlol and 45% 'of recovered butynediol suitable for reuse in the. same process.

. This invention has been disclosed with respect to certain preferred embodiments, and there will become obvious to persons skilled in the art various modifications, equivalents or variations thereof which are intended to be included within the spirit and scope of this invention.

I claim:

1. A process for the catalytic hydrogenation of 1,4- butynediol to 1,4-butenediol consisting in treating butynediol with hydrogen at a temperature of about 60 to 120 C. and a pressure of about 0 to 6 atmospheres gauge in the presence of a nickel catalyst carrying about 3 to 15% of copper by weight thereof, the maximum pressure being 2 atmospheres gauge at temperatures of 60 up to but not including 80 C., 4 atmospheres gauge at temperatures of 80 up to but not including 100 C., and 6 atmospheres gauge at atemperatures of 100 to 120 C.

2, A process as defined in claim 1 wherein the nickel catalyst is a Raney-type nickel catalyst.

3. A process for the catalytic hydrogenation of 1,4-

butynedlol to 1,4-butenediol consisting in treating a solution of 1,4-butynediol with hydrogen at a temperature of about 60 to 120 C. and a pressure of about 0 to 6 atmospheres gauge in the presence of a nickel catalyst, the

maximum pressure being 2 atmospheres gauge at temperbutynediol to 1,4-butened3ol consisting in treating an aqueous solution of 1,4-butynediol with hydrogen at a temperature of about to 120 C. and a pressure of about 0 to 6 atmospheres gauge in the presence of a nickel catalyst, the maximum pressure being 2 atmospheres gauge at temperatures of 60 up to but not including C., 4 atmospheres gauge at temperatures of 80 up to but not including C., and 6 atmospheres gauge at temperatures of 100 to C.

6. A process as defined in claim 5 wherein a Raneytype nickel catalyst is employed.

7. A process for the catalytic hydrogenation of 1,4- butynedlol to 1,4-butenediol consisting in treating an aqueous solution of 1,4-butynediol with hydrogen at a temperature of about 60 to 120 C. and a pressure of about 0 to 6 atmospheres gauge in the presence of a nickel catalyst carrying about 3 to 15% of copper by weight of the nickel catalyst, the maximum pressure being i 2 atmospheres gauge at temperatures of 60 up to but not including 80 C., 4 atmospheres gauge at temperatures of 80 up to but not including 100 C., and 6 atmospheres gauge at temperatures of 100 to 120 C.

. 8. A process as defined in claim 7 wherein the nickel F catalyst is a Raney-type nickel catalyst.

References Cited in the file of this patent -UNITED STATES PATENTS 2,157,365 Vaughn May 9, 1939 2,319,707 Reppe et al May 18, 1943 2,335,795 Reppe et a1 Nov. 30, 1943 2,737,534 Taylor et al Mar. 6, 1956 FOREIGN PATENTS 508,944 Great Britain June 26, 1939 869,053 Germany Mar. 2, 1953 OTHER REFERENCES Campbell et al.: Chemical Reviews, vol. 31, pages -51 (1942).

I Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 236L471 November 22 1960 Eugene V Hort It is h'ereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 62 for "CD/mm. read me (lo/2mm, m

Signed and sealed this 30th day of May 1961.,

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Commissioner of Patents 

1. A PROCESS FOR THE CATALYTIC HYDROGENATION OF 1,4BUTYNEDIOL TO 1,4-BUTENEDIOL CONSISTING IN TREATING BUTYNEDIOL WITH HYDROGEN AT A TEMPERATURE OF ABOUT 60 TO 120* C. AND A PRESSURE OF ABOUT 0 TO 6 ATMOSPHERES GAUGE IN THE PRESSURE OF A NICKEL CATALYST CARRYING ABOUT 3 TO 15% OF COPPER BY WEIGHT THEREOF, THE MAXIMUM PRESSURE BEING 2 ATMOSPHERES GUAGE AT TEMPERATURES OF 60 UP TO BUT NOT INCLUDING 80*C., 4 ATMOSPHERES GAUGE AT TEMPERATURES OF 80 UP TO BUT NOT INCLUDING 100*C., AND 6 ATMOSPHERES GAUGE AT TEMPERATURES OF 100 TO 120*C. 